Drill sharpener



Jul so, 1957 1.11pm 2,800,755

DRILL SHARPENER Filed March 14,- 1955 Y s sheets-sheet 1 Fig.1 .El

INVENTOR JbsepHlD. Ferra- ATTORNEYS I July 30, 1957 PERRA 2,800,755

DRILL SHARPENER Filed March 14, 1955 3 Sheets-Sheet 2 25 i; jwwiz zxs ATTORNEYS y 0, 1957 J. D. PERRA 2,800,755

' DRILL SHARPENER Filed March 14, 1955 a Sheets-Sheet s INVENTOR 5 6:19}! Perra BY .MLrtu-zl,

- A'n'bnusvs DRILL SHARPENER Joseph D. Perra, Monterey, Calif. Application March 14, 1955, Serial No. 493,970

Claims. ((11. 51-241 This invention relates to a tool for sharpening twist drills; my main object being to provide a device for the purpose arranged to be mounted on an electric hand drill or similar tool, and which device includes a member to support a drill to be sharpened, and an abrasive disc or wheel driven by the tool on which the device is mounted.

A further object of the invention is to arrange the drill holding member of the device so that a number of drills, of different sizes, may be sharpened simultaneously if desired.

Another object of the invention is to provide means whereby the drill-engaging face of the abrading wheel may be dressed when necessary without removing the same from the tool.

Still another object of the invention is to provide a drill sharpener which is designed for ease and economy of manufacture, and is readily portable.

It is also an object of the invention to provide a practical and durable drill sharpener, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig. 1 is a side elevation of the drill sharpener as connected to an electric hand drill for operation thereby.

Fig. 2 is a rear end elevation of the device, detached from the supporting and operating tool.

Fig. 3 is a front end elevation of the device.

Fig. 4 is a sectional elevation of the sharpener on line 4-4 of Fig. 3. e

Fig. 5 is a fragmentary section on line 5-5 of Fig. 3,

i and showing a drill in sharpening position.

Fig. 6 is a fragmentary sectional elevation similar to Fig. 4, but showing the blade for dressing the abrading wheel in position for operation. I

Fig. 7 is a fragmentary cross section on line 7-7 of Fig. 6.

Fig. 8 is a sectional view showing a modified form of adjustment for the abrading wheel. V

Fig. 9 is a fragmentary sectional view on line 9-'-9 of Fig. 8.

Referring now more particularly to the characters of reference on the drawings, the drill sharpener comprises a cylindrical cup-like body I initially open at its outer end and including a bottom plate 2 and a hub 3 projecting back from plate 2. A trough-like extension 4 projects back from the hub and is arranged at its rear end to receive the body 5 of an electric hand-drill indicated generally at 6; said body being releasably clamped in the sleeve by a suitable clamping unit 7 provided with extension 4 at its rear end. The length and size of the extension 4, between the hub 3 and the clamping unit 7,

.is sufficient to receive the chuck 8 of drill 6 in clearance relation, and so that said chuck is axially alined with body 1.

Seated in the outer portion of body 1 is a headstock block 9, removably secured in place by set screws 10 or the like. The headstock block is arranged to mount a nited States Patent 2,800,755 Patented July 39, 1957 number of drills for sharpening in a manner which will be described later. Disposed in body 1 between block 9 and bottom plate 2, in clearance relation to both thereof, is an abrading wheel 11. A supporting and driving stem 12 is secured to the wheel 11 axially thereof and projects from the back end thereof through a bushing 13 in hub 3 for gripping engagement by chuck 8 of tool 7.

Hub 3 is formed with a socket 14 about the stem 12 and open to body 1, and a compression spring 15 about the stem in said socket tends to force the wheel 11 forwardly and toward block 9.

The spring action is resisted by a spindle 16 mounted in block 9 axially thereof, and which spindle engages an exposed head 17 on the inner end of stem 12. Spindle 16 is adjustably threaded into the block 9 for adjustment lengthwise or axially thereof, and is provided with a knob 18 on its outer end whereby such adjustment may be effected to alter the spacing between the headstock and wheel. A retaining nut 19 on the spindle enables the spindle to be held in any position of adjustment. The forward working face 20 of the abrading wheel 11 is conically socketed on an angle of 59 to the axis of the wheel, as shown; this being the angle of the work-entering end or tip 21 of a standard twist drill 22. The adjacent rear face of the block is similarly angled so as to be parallel to face 20 as shown in Fig. 4.

Drills 22 to be sharpened are supported in block 9 in proper position for the tips 21 thereof to be flatly engaged by the working face 20 of the wheel 11, in the following manner, as shown particularly in Fig. 5.

For each such drill, a tubular member 23 is secured in the block 9 and projects entirely therethrough; the bore of such member, being of a size to snugly fit a drill 22 of a certain diameter, but being considerably shorter than such drill. For best results, the axis of the member 23, while extending lengthwise of and parallel to the axis of the block and of the wheel 11 in one direction, is set in the block at an angle of approximately 12 to the axis of the wheel tangentially of the periphery of the block in a direction opposite the direction of rotation of the wheel, as indicated in Figs. 3 and 5.

Disposed over the outer end 'of member 23 and held in place by a cap 24 screwed onto said member 23, as shown in Fig. 5, is a washer 25 having inwardly projecting cars 26 shaped to engage in the opposed flutes 22a of drill 22, and which flutes extend to the tip of the drill and divide the taper portion of the tip into two diametrally opposed sections, as usual. When drill 22 is to be sharpened, it must therefore be advanced through the member 23 and into contact with the wheel 11 by rotating the drill in the manner of a screw turning through a nut. The ears 26 are set so that when the drill is fully advanced, one section of the taper tip 21 will be in the proper sharpening position against the abrading wheel.

In practice a drill is advanced and one section of the tip is held lightly against the abrading wheel for a moment. This sharpens the tip on that section. A collar 27 is then mounted on the drill and moved against cap 24 and locked in that position by set screw 28. The drill is then withdrawn from member 23, rotated a half turn, and reinserted into member 23. This will place the other section of tip 21 in contact with the abrading wheel. The collar 27 limits advance of the drill further than proper sharpening requires, and so that both tip sections are symmetrically sharpened.

As shown in Fig. 3, a plurality of the drill receiving members 23 are mounted in the block 9, each being bored to receive a drill of a different standard size. Said members are set in spiral form about the axis of the body as shown, so as to bring the major portion of the area of the working face 20 of the abrading wheel into play at one time or another.

In order to enable the face 20 of the wheel to be dressed when necessary without taking the device apart,

the block 9, between adjacent members 23, is provided with a radial groove 29 parallel to face 20 and arranged to receive a dressing tool in the form of a groove-fitting shank 30 having a blade portion 31 projectingtherefrom at one end for engagement with the face 20, as shown in Fig. 6. The shank 30 is longer than groove 29 and the body is provided with an opening 32 registering with said groove so that the shank may be inserted in or removed from the groove at will, and pulled back and forth manually, as the abrading wheel rotates, so that the blade 31 will traverse the entire radial extent of the wheel 11.

Adjacent the forward end of the wheel 11 the body 1 is provided with a number of holes 33 through which metal and abrading dust may be discharged.

The body 1 is formed with an opening 34 in its bottom and side to expose the rear and side of abrading wheel 11. This permits the wheel to be made useful in thinning the web of a drill point after the length of the drill has lessened to a point where this becomes necessary.

In Figs. 8 and 9 there is disclosed a modification of the adjusting means for the abrading wheel 11. Here, instead of the simple elements 1618, shownfor example-in Fig. 4, there may be used a substitute structure which will positively meter the movement of the abrading wheel 11 relative to block 9, so that the space between the two may be always adjusted to the same relative width after each resurfacing of the abrading wheel, as will appear.

"In this form of adjusting means the front face of the block 9 centrally thereof is provided with a recess 35. Centrally of this recess is disposed a spindle, indicated generally by the numeral 36. This spindle 36 is threaded through the block 9, as at 37, and its inner end engages the head 17 against the resistance afforded by the spring 15. A square shank 38 extends outwardly from the threaded portion 37, through recess 35, and to a termination outwardly of the block 9, where it is provided with a knurled head 39.

Within the recess 35 is a flat band spring 40 bent into a U-shape, with the flat sides of the spring frictionally and yieldably engaging the flat sides of shank 38, as clearly shown in Fig. 9. The spring 40 is held from turning in the recess 35 by projecting points 41 which extend into the holes 42 in the bottom of the recess 35.

The spring 40 is held in its operative position within the recess 35 by means of a nut 43 threaded into the recess 35 and against the spring. The bottom of this nut V and the bottom of the recess 35 are both slightly concaved, as at 44 and 45, respectively, so as to allow freedom of action of the spring. The action of the spring is such as to allow the spindle to be manually turned as desired, but to hold against undesired turning from any selected position to which it may be turned.

' The structure just described is useful in permitting the abrading wheel 11 to be always set at the most desirable fixed distance from the block 9 after each dressing of the face of the abrading wheel in the manner previously described. How this fixation of such space is accomplished will now be described.

When the abrading wheel is to be dressed the head 39 is turning clockwise to cause spindle 36 to advance and carry the abrading Wheel 11 against the resistance of spring 15 until there is sufficient clearance to admit entry of the dressing tool 3031 into the groove 29. With the wheel 11 held quiescent the dressing tool is then entered as far as possible into the groove 29. The motor is then started to drivethe abrading wheeland the spindle 36 is backed away until the wheel 11 contacts the dressing blade 31. The dressing tool is then slowly withdrawn from groove 29, dressing the abrading wheel as it goes. I

When the dressing operation is complete the spindle 36 is backed off until the surface of the abrading wheel commences to drag on the adjacent face of the block 9,

The spindle 36 is then turned one-quarter turn so as to cause the abrading wheel to back away from the block 9 a predetermined distance which is deemed best to the efficient operation of the sharpener. Once determined, this distance will always be constant because of the relative structural detail between the spring 40 and square shank 38. The spring yields to allow the quarter-turn of the shank, then snaps back against the flat side of the shank to prevent further uncontrolled turning of the latter.

From the foregoing description it will be readily seen that there has been provided such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new'and useful and upon which Letters Patent are desired.

1. A sharpener for twist drills comprising a supporting body, a headstock block secured in the body, an abrasive wheel turnably mounted in the body back of the block and having a. working surface disposed in facing relation to the block, means connected to the wheel to rotate the same, and means in the block to support a drill in such position that a portion of the tip thereof will flatly engage said working surface; said drill supporting means comprising an open-end tubular member mounted in the block and projecting from the front face thereof, said member being bored to fit a drill of a certain size and shorter than the fluted portion of such drill, and a washer secured on the forward end of the member, said washer having opposed ears projecting radially inward to engage in the opposed flutes of the'drill. 2. A sharpener for twist drills Comprising a supporting body, a headstock secured in the body, an abrasive wheel turnably mounted in the body back of the block and having a working surface disposed in facing relation to the block, means connected to the wheel to rotate the same, and means in the block to support a drill in such position that a portion of the tip thereof will flatly engage said Working surface; the block being formed with aradial groove in the face thereof, nearest the abrading wheel and disposed parallel to the working surface thereof, to receive a dressing blade for said working surface; the body having an opening registering with said groove to receive such blade therethrough. 1

3. A twist drill sharpener for use with an operating tool which includes a body and a rotary chuck projecting from the forward end thereof; said sharpener comprising a cylindrical body having a back plate at its rear end and a hub projecting rearwardly from said plate, a headstock block mounted in the forward portion of the body, a rotary abrading wheel disposed in the body between the block and the back plate, means in the block to support a drill with its tip in engagement with the wheel for sharpening, a spindle rigid with the wheel axially thereof :and projecting rearwardly therefrom, means jonrnaling the spindle in the hub, a trough-like extension projecting 'rearwardly from the body and hub and rigid therewith, and means on the extension at its rear end to clampingly .engage the body of the tool at its forward end so that ment, means connected to the wheel to rotate the same,

means in the block to support a drill with a portion of the tip thereof in sharpening engagement with said working surface of the wheel, spring means urging the wheel forwardly toward the block, and an axially adjustable element mounted in the block and engaging the wheel to resist the spring action and affect the forwardly urging pressure thereof.

5. A sharpener, as in claim 3, with a cap on the member holding the washer in position, and a collar arranged to be removably clamped on the drill to engage the cap and limit the advancing movement of the drill toward the working surface of the wheel.

References Cited in the file of this patent UNITED STATES PATENTS Pickering July 31, 1883 Smith June 17, 1924 Reeves Sept. 16, 1924 Williams Mar. 19, 1935 Baalrnann Apr. 27, 1937 Allen Dec. 15, 1942 Johnson Dec. 20, 1949 Douglas June 27, 1950 Trippel Apr. 8, 1952 Lohr July 1, 1952 

